Method for producing radically post-cross-linked polymers

ABSTRACT

Radically post-crosslinked polymers are made by a process comprising the steps of: (1) forming a polyurethane (a*) by reacting a compound (a) with an aliphatic and/or an aromatic isocyanate and a compound (c) wherein compound (a) is the product of the reaction of an epoxidized fatty acid ester and/or an epoxidized triglyceride with acrylic acid and/or methacrylic acid and wherein compound (c) is a polyol ester having two or more C═C double bonds per molecule; (2) forming a crosslinked polyurethane by reacting the polyurethane (a*) with a radical initiator (b). The polymers are useful as components in composites comprised of natural and/or synthetic fibers.

FIELD OF THE INVENTION

[0001] This invention relates to a process for the production ofradically post-crosslinked polymers. In the process according to theinvention, one or more special acrylic or methacrylic acid derivativesbased on naturally occurring oils is/are reacted with aromatic and/oraliphatic isocyanates and the polyurethanes thus obtained aresubsequently subjected to radical post-crosslinking in the presence of aradical initiator.

PRIOR ART

[0002] The use of radiation curing in the coating industry for producinghigh-quality coating materials is known from the prior art. In radiationcuring, olefinically unsaturated compounds (monomers, oligomers,polymers, prepolymers), i.e. compounds containing C═C double bonds asstructural elements, are cured by exposure to high-energy radiation, forexample UV light or electron beams. The actual radiation curing processis sometimes preceded by physical drying.

[0003] It is also known that particularly high-quality coatings areobtained in radiation curing when the olefinically unsaturated startingcompounds used contain polyurethane groups as further structuralelements. Unsaturated radiation-curable urethane acrylates are knownfrom Manfred Bock (Ed. Ulrich Zorill), “Polyurethane für Lacke undBeschichtungen”, Hannover 1999, pages 73-74.

[0004] U.S. Pat. No. 3,979,270 describes a process for the curing ofamine derivatives of reaction products of acrylated epoxidized soybeanoil in which curing is carried out by high-energy radiation.

DESCRIPTION OF THE INVENTION

[0005] The problem addressed by the present invention was to provide aprocess for the production of polymers with excellent properties, moreparticularly in regard to impact strength, hydrophobia, chemicalstability and resistance to water or water vapor. In addition, theirspecial performance properties would enable these polymers to be used asmatrix materials for composites.

[0006] The problem stated above has surprisingly been solved by aprocess in which OH-functional oleochemical compounds, which consist ofreaction products of epoxidized fatty acid esters and/or epoxidizedtriglycerides with acrylic acid and/or methacrylic acid and whichtherefore contain both one or more hydroxyl groups and one or more C═Cdouble bonds per molecule, are reacted with aliphatic and/or aromaticisocyanates (which in the context of the invention are understood to beany isocyanates known to the relevant expert, i.e. compounds whichcontain one or more —N═C═O— groups) and the compounds thusobtained—hereinafter referred to in short as “polyurethanes” (a*)—aresubsequently subjected to radical post-crosslinking in the presence of aradical initiator (b).

[0007] The present invention relates to a process for the production ofradically post-crosslinked polymers, characterized in that, in a firststage, one or more compounds (a) which are reaction products ofepoxidized fatty acid esters and/or epoxidized triglycerides withacrylic acid and/or methacrylic acid are converted into thecorresponding polyurethanes (a*) by reaction with aliphatic and/oraromatic isocyanates and, in a second stage, the polyurethanes (a*) thusproduced are subsequently subjected to radical post-crosslinking in thepresence of at least one radical initiator (b).

[0008] The term “subsequently” in the context of the present inventionsimply means that the second stage of the process according to theinvention follows the first stage. It is not intended to signify anylimitation in the time sense. Accordingly, the second stage of theprocess according to the invention may be carried out both immediatelyafter the first stage and—depending on the intended application—afterstorage of the intermediate product (a polyurethane) obtained in thefirst stage, the storage time being basically unlimited.

[0009] The production of epoxidized fatty acid esters or epoxidizedtriglycerides has been known for some time. To this end, esters ofolefinically unsaturated fatty acids or triglycerides which containolefinically unsaturated fatty acids as fatty acid units are subjectedto epoxidation, one or more double bonds per molecule being convertedinto oxirane groups.

[0010] Preferred fatty acid units of the fatty acid esters to beepoxidized are C₁₂₋₂₄ carboxylic acids which contain at least oneolefinic double bond in the molecule. The triglycerides to be epoxidizedare preferably triglycerides where at least one fatty acid unit pertriglyceride molecule contains at least one olefinic double bond.

[0011] Examples of suitable epoxidized triglycerides are the epoxidationproducts of the following unsaturated oils: soybean oil, linseed oil,tall oil, cottonseed oil, peanut oil, palm oil, sunflower oil (from oldand new plants), rapeseed oil and neatsfoot oil. Production is carriedout in particular by reacting the unsaturated oils mentioned withperformic acid or peracetic acid. Preferred triglycerides are those withan iodine value of 50 to 200 which are converted by epoxidation of mostof the olefinic double bonds into epoxides with an epoxide oxygencontent of 3 to 10% by weight.

[0012] Particularly preferred epoxidized triglycerides are epoxidizedsoybean oil (for example “Edenol D 81”, a product of Cognis DeutschlandGmbH and formerly of Henkel KGaA) and epoxidized linseed oil (forexample “Edenol B 316”, a product of Cognis Deutschland GmbH andformerly of Henkel KGaA).

[0013] The addition of acrylic and/or methacrylic acid onto theepoxidized fatty acid esters or epoxidized triglycerides mentioned togive the compounds (a) is known per se to the expert. It may be carriedout in such a way that the oxirane rings are completely or partlyopened. In the event of partial ring opening, preferably at least 50% ofthe oxirane rings are opened. In a particularly preferred embodiment,however, the addition of acrylic and/or methacrylic acid onto theepoxidized fatty acid esters or epoxidized triglycerides mentioned iscarried out in such a way that more or less all the oxirane rings areopened and converted into HO—CH₂—CH₂—OR groups in which R is an acrylateor methacrylate residue.

[0014] In a particularly preferred embodiment of the present invention,the ring opening product of epoxidized soybean oil with acrylic acidwhich has a hydroxyl value of about 158 mg KOH/g substance is used asthe acrylated oil (a). This acrylate is first reacted with aromaticand/or aliphatic isocyanates, a catalyst, for example an organotincompound, preferably being used in the case of the aliphaticisocyanates.

[0015] As already mentioned, one or more (meth)acrylated compounds (a)are subjected to a two-stage treatment in the process according to theinvention, namely:

[0016] first a reaction with aliphatic and/or aromatic isocyanates

[0017] and then radical post-crosslinking of the polyurethanes (a*)obtained in the presence of at least one radical initiator (b).

[0018] The choice of the isocyanates is not subject to any particularlimitations. In principle, therefore, any isocyanates known to therelevant expert, i.e. compounds containing one or more —N═C═O— groups,may be used.

[0019] Diisocyanates, oligo- or polyisocyanates and mixtures of thesecompounds are preferably used. Polyisocyanates in the context of theinvention include, for example, adducts of diisocyanates withtrimethylolpropane, biurets, uretdiones (cyclodimerized isocyanates),isocyanurates (cyclotrimerized isocyanates), allophanates,carbodiimide-based isocyanates and the like (with regard to expertknowledge on the subject of di- and polyisocyanates, reference is madepurely by way of example to: Ullmanns Encyklopädie der technischenChemie, Vol. 19, 4th Edition, Weinheim 1980, pages 302-304 and toKirk-Othmer, Encyclopedia of Chemical Technology, 4th Edition, New York1995, Volume 14, pages 902-934 and finally to Gerhard W. Becker [Ed.],Kunststoff-Handbuch, Vol. 7: “Polyurethane” [edited by Günter Oertel],3rd Edition, Munich 1993, pages 11-21, 76-103). Particular reference ismade to commercially available polyisocyanates, for example polymer-MDIand the like which are commercially available in various degrees ofpolymerization.

[0020] Preferred diisocyanates are compounds with the general structureO═C═N—X—N═C═O where X is an aliphatic, alicyclic or aromatic radical,preferably an aliphatic or alicyclic radical containing 4 to 18 carbonatoms.

[0021] Suitable diisocyanates are, for example, 1,5-naphthylenediisocyanate, 4,4′-diphenylmethane diisocyanate (=methylene diphenylenediisocyanate, MDI), hydrogenated MDI (H₁₂MDI, a cycloaliphaticcompound), xylylene diisocyanate (XDI), tetramethyl xylylenediisocyanate (TMXDI), 4,4′-diphenyldimethylmethane diisocyanate, di- andtetraalkyl diphenylmethane diisocyanate, 4,4′-dibenzyl diisocyanate,1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, the isomers oftoluene diisocyanate (TDI, more particularly the technical isomermixture of essentially 2,4- and 2,6-toluene diisocyanate),1-methyl-2,4-diisocyanatocyclohexane,1,6-diisocyanato-2,2,4-trimethylhexane, 1,6-diisocyanato-2,4,4-trimethylhexane, 1-isocyanatomethyl-3-isocyanato-1,5,5-trimethyl cyclohexane(isophorone diisocyanate=IPDI), chlorinated and brominateddiisocyanates, phosphorus-containing diisocyanates,4,4′-diisocyanatophenyl perfluoroethane,tetramethoxybutane-1,4-diisocyanate, butane-1,4-diisocyanate,hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate,cyclohexane-1,4-diisocyanate, ethylene diisocyanate, phthalicacid-bis-isocyanatoethyl ester, diisocyanates containing reactivehalogen atoms, such as 1-chloromethylphenyl-2,4-diisocyanate,1-bromomethylphenyl-2,6-diisocyanate,3,3-bis-chloromethyl-ether-4,4′-diphenyl diisocyanate. Sulfur-containingpolyisocyanates are obtained, for example, by reaction of 2 molhexamethylene diisocyanate with 1 mol thiodiglycol or dihydroxydihexylsulfide. Other important diisocyanates are trimethyl hexamethylenediisocyanate, 1,4-diisocyanatobutane, 1,12-diisocyanatododecane anddimer fatty acid diisocyanate (“Sovermol DD11410”, a product of CognisDeutschland GmbH and formerly of Henkel KGaA). Particularly suitablediisocyanates are tetramethylene, hexamethylene, undecane,dodecamethylene, 2,2,4-trimethylhexane, 1,3-cyclohexane,1,4-cyclohexane, 1,3- or 1,4-tetramethyl xylene, isophorone,4,4-dicyclohexyl methane and lysine ester diisocyanate.

[0022] One embodiment of the present invention is characterized by theuse of isocyanates of relatively high functionality, i.e. isocyanateswith an average NCO functionality of at least 2.0. These include inparticular all commercially available polyisocyanates (for examplepolymer-MDI and the like and the polyisocyanates of formula 1 to 7disclosed in EP-A438 836) which have an NCO functionality above 2.0. Theexpert speaks in terms of an average NCO functionality because thecorresponding isocyanates of relatively high functionality do notnecessarily have to be present in the form of chemically uniform“individuals”, such as cyclotrimerized isocyanates for example, butinstead are often mixtures of different chemical individuals each withdefined NCO functionalities, particularly in the case of commerciallyavailable technical products.

[0023] In the reaction of the (meth)acrylated compounds (a) withaliphatic and/or aromatic isocyanates to form the polyurethanes (a*),the reaction ratios between the components (a) and the isocyanates areselected so that the equivalent NCO:OH ratio is in the range from 0.03:1to 1.2:1 and preferably of the order of 0.4:1.

[0024] In a preferred embodiment of the present invention, a combinationof at least one compound (a) with at least one compound (c) is used inthe first stage of the process according to the invention, with theproviso that (c) is selected from polyol esters containing two or moreC═C double bonds per molecule. It is expressly pointed out in thisconnection that the compounds (c) are substances which do not fall underthe definition of the substances (a) to be used in accordance with theinvention, i.e. which are different from those substances (a). Thepolyol esters (c) may be both full esters and partial esters with theabove-mentioned proviso in either case that two or more C═C double bondsper molecule must be present per molecule of polyol ester. If components(c) containing one or more free hydroxyl groups besides the C═C doublebonds are used, the foregoing observations on the equivalent NCO:OHratio are applicable in the sense that they apply to the sum of thecompounds (a) and (c) and not just to the compounds (a) alone.Polyurethanes which may be termed a mixture of (a*) and (c*) are thusformed in the first stage of the process according to the invention,(a*) having the meaning mentioned above and (c*) analogously signifyingthe polyurethanes arising out of the reaction of the polyol esters (c)with isocyanates which contain one or more free hydroxyl groups besidesthe C═C double bonds.

[0025] One embodiment is characterized by the use of compounds (c)obtainable by esterification of polyols containing 2 to 6 OH groups withacrylic and/or methacrylic acid. In a preferred embodiment, thecompounds (c) contain as polyol units polyols containing 2 to 6 OHgroups which have a molecular weight below 1,000. Examples of suitablepolyol units belonging to this group are ethylene glycol, propyleneglycol, butanediol, neopentyl glycol, glycerol, trimethylol propane,sugars such as, for example, pentaerythritol, sorbitol or glucose andpolyalkylene glycols.

[0026] A particularly preferred compound (c) is dipropylene glycoldiacrylate. It is also pointed out that the polyol esters (c) to be usedin accordance with the invention may be used individually or incombination with one another.

[0027] In another preferred embodiment of the present invention, acombination of at least one polyurethane (a*) with at least one of thepolyol esters (c) mentioned is used in the second stage of the processaccording to the invention. The compounds (c) used in the second stagemay be both compounds specifically added to the compounds (a*) andcompounds (c) which, although used in the first stage, remainedunchanged in the course of the urethanization reaction because they werefree from hydroxyl groups.

[0028] The post-crosslinking of the polyurethanes (a*) obtained in thefirst stage of the process according to the invention is carried out inthe presence of at least one radical initiator (b). Basically, thechoice of this initiator is not critical. However, an organic peroxideis preferably used as the radical initiator. Organic peroxides arecommercially available in large numbers. Reference is made by way ofexample to the substances marketed by Peroxid-Chemie GmbH, moreparticularly methyl ethyl ketone peroxide (MEKP), acetyl acetoneperoxide, cyclohexanone peroxide, dibenzoyl peroxide, tert.butylperoxybenzoate, bis-(4-tert.butylcyclohexyl)-peroxydicarbonate,dimyristyl peroxydicarbonate,2,5-dimethyl-2,5-di-(2-ethylhexanoylperoxy)-hexane,tert.amylperoxy-2-ethyl hexanoate, methyl isobutyl ketone peroxide,tert.butylperoxy-2-ethyl hexanoate (TBPEH), cumene hydroperoxide,tert.butylperisononanoate (TBPIN), tert.butylperoxybenzoate,tert.butylcumyl peroxide. MEKP, TBPEH and TBPIN are particularlypreferred.

[0029] In one embodiment, the post-crosslinking of the polyurethanes(a*) obtained in the first stage of the process according to theinvention is carried out in the presence of 0.1 to 10% by weight—basedon the polyurethane (a*) used—of one or more radical initiators (b). Thepost-crosslinking step may be carried out by any of the relevant methodsknown to the expert.

[0030] At low to medium temperatures in the range from about 20 to 100°C. and more particularly 20 to 70° C., the post-crosslinking step ispreferably carried out in the presence of a catalyst (=reactionaccelerator). Preferred catalysts are transition metal compounds (d).The quantity of transition metal compound used—metal content of thetransition metal compound based on the polyurethane obtained in thefirst stage of the process according to the invention—is 0.01 to 1,000ppm. Basically, there are no particular limitations as to the type oftransition metal compound used. Accordingly, any transition metalcompounds known to the expert may in principle be used for the purposesof the teaching of the present invention. In one embodiment, transitionmetal salts, preferably salts based on organic acids containing 6 to 22carbon atoms, are used as the transition metal compounds. Anotherembodiment is characterized by the use of transition metal compounds ofwhich the metals are selected from the group consisting of cobalt,zirconium, iron, lead, manganese, nickel, chromium, vanadium, cerium,titanium and tin. A particularly preferred catalyst is cobalt(II)octoate which is used in particular in the form of a solution, forexample in phthalate.

[0031] In another embodiment, the post-crosslinking step is carried outin the absence of a catalyst at temperatures in the range from 60 to160° C. and more particularly at temperatures in the range from 120 to160° C. This special form of crosslinking may be regarded as hot curing.The brief heating to temperatures of about 150° C. is of particularadvantage in that, typically, reaction times of only a few minutes arerequired at those temperatures. A particular advantage of hot curing isthat post-crosslinkable resins containing components (a*)—if desired incombination with (c) and/or (c*)—and also (b) and optionally (e) are farmore stable in storage than systems additionally containing component(d).

[0032] In one embodiment, the second stage of the process according tothe invention is carried out in the presence of one or more compounds(e) capable of radical copolymerization with the unsaturatedpolyurethanes (a*). Suitable compounds (e) are, in particular,substances containing one C═C double bond per molecule, preferablyacrolein, acrylamide, vinyl acetate and styrene. These compounds may beused individually or in the form of mixtures with one another.

[0033] In one embodiment, the first and/or second stage of the processaccording to the invention is carried out in the presence of up to 20%by weight of additives typical of plastics—% by weight of the sum of allplastics additives, based on the total quantity of compounds (a) used.Additives such as these include, for example, thickeners, flow controlagents, defoamers, lubricants, fillers, UV stabilizers and aresufficiently well-known to the expert from paint and coating technology.It is important to ensure that the additives used are largely free fromhydroxyl groups where they are used in the first stage of the process sothat they do not react off with the isocyanates used in this stage.

[0034] In one embodiment, a mixture of the polyurethanes (a*) obtainedin the first stage of the process according to the invention incombination with the desired radical initiators (b) and optionally thedesired compounds (c) to (e) is applied in the required layer thicknessto a solid substrate and the post-crosslinking step is subsequentlycarried out—immediately or after storage. Suitable solid substrates are,in particular, wood, paper, plastic surfaces, mineral buildingmaterials, such as cement bricks or cement fiber boards, metals orcoated metals. If desired, the post-crosslinking step, which may also bereferred to as curing, may be repeated one or more times. Theapplication of the polyurethanes (a*) in admixture with the desiredradical initiators (b) and optionally the desired compounds (c) to (e)to the solid substrate is carried out in known manner, for example byspray coating, trowelling, knife coating, brush coating, roller coatingor casting. The coating thickness is generally in the range from 3 to500 g/m² and more particularly in the range from 10 to 200 g/m² or wetfilm thicknesses of about 3 to 500 μm and more particularly 50 to 200μm. The coating may be applied both at room temperature and at elevatedtemperature, but more particularly not above 100° C.

[0035] In another embodiment of the process according to the invention,the second stage of the process is carried out by impregnating syntheticand/or natural fibers with a mixture of components (a*), (b) andoptionally (c) and/or (c*) and/or (e) and optionally plastics additivesand then carrying out the radical crosslinking step. This procedure isbased on so-called prepreg technology. A prepreg is a semifinishedproduct preimpregnated with thermoplastic or thermoset material which isconverted into the end product in another processing step. To produceprepregs, fibers are impregnated with a resin matrix in suitableinstallations. The prepregs may then either be processed to the desiredend products either immediately after their production or after storagefor a certain period. Accordingly, the objective of this particularembodiment of the invention is to provide fiber composites of fibers anda matrix material in which the matrix material is a radicallypost-crosslinked polymer obtainable by the process according to theinvention.

[0036] The present invention also relates to the use of polymersobtainable by the process according to the invention as matrix materialfor composites based on synthetic and/or natural fibers.

[0037] The present invention also relates to a polymer-based materialobtainable by a process in which, in a first stage, at least one or morecompounds (a) which are reaction products of epoxidized fatty acidesters and/or epoxidized triglycerides with acrylic acid and/ormethacrylic acid are converted into the corresponding polyurethanes (a*)by reaction with aliphatic and/or aromatic isocyanates and, in a secondstage, the polyurethanes (a*) thus produced are subsequently subjectedto radical post-crosslinking in the presence of at least one radicalinitiator (b).

[0038] The foregoing observations on the process according to theinvention apply in regard to the individual parameters and thesubstances compulsorily or optionally used in the production of thematerial according to the invention.

[0039] In another embodiment, the production of the polymer-basedmaterial in the second stage is carried out in the presence of syntheticand/or natural fibers on the lines of the prepreg technology mentionedabove. Basically, no particular limitations apply to the fibers. Thus,both synthetic fibers, such as glass fibers, carbon fibers, metal fibersand the like, and natural fibers may be used. According to theinvention, preferred fibers are those which at least partly butpreferably completely contain natural fibers. These natural fibers maybe used in the form of short fibers, yarns, rovings or preferablysheet-form textiles in the form of nonwovens, needle-punched nonwovens,random laid nonwovens, woven fabrics, laid fabrics or knitted fabrics.According to the invention, natural fibers are preferably selected fromflax, hemp, straw, wood wool, sisal, jute, coconut, ramie, bamboo, bast,cellulose, cotton or wool fibers, animal hair or fibers based onchitin/chitosan and combinations thereof. Materials partly or completelycontaining flax fibers are preferred. The percentage by weight offibrous material in the prepregs is between 10 and 70% by weight, basedon the total quantity of compounds (a), (b) and optionally (c) used.

[0040] The fibers may be contacted with the matrix by any methods knownto the expert in order to obtain the prepregs. The fibers are preferablydipped in the matrix but may also be sprayed with the matrix. Mixturescontaining (a*), (b) and optionally (c) which have a Brookfieldviscosity of 600 to 1,400 mPas (as measured with spindle 5 at 10 r.p.m.)are preferably used. The viscosity values are all based on theapplication temperature. The matrix is applied to the fibers attemperatures of preferably 40 to 80° C. In one particularly advantageousembodiment, the matrixes selected have a Brookfield viscosity of 600 to1,200 mPas at a temperature of 65° C. This ensures that the matrixes donot yet cure completely. Instead, the prepregs initially obtained canstill be molded as required which simplifies their subsequentprocessing. In addition, the prepregs do not cure as quickly in air atroom temperature as known prepregs and thus show distinctly increasedstability in storage.

[0041] The materials obtainable as just described where the second stageof the production process is carried out in the presence of syntheticand/or natural fibers may be termed fiber composites. By virtue of theirexcellent performance properties, these fiber composites have a numberof applications. Accordingly, the present invention also relates to theuse of these fiber composites for the production of structuralcomponents for vehicle and aircraft construction, the building industry,window manufacture, the furniture industry, the electronics industry,sports equipment, toys, machine construction, the packaging industry,agriculture or the safety sector.

EXAMPLES

[0042] A) Substances Used

[0043] A1) Products of Cognis Deutschland GmbH

[0044] Photomer 3005 F:

[0045] Ring opening product of epoxidized soybean oil with acrylic acid

[0046] Photomer 4226:

[0047] Dipropylene glycol diacrylate

[0048] A2) Other Products

[0049] Beschleuniger (“accelerator”) C-101:

[0050] Solution of cobtalt(II) octoate in phthalate; Co content=1% byweight (Peroxid-Chemie GmbH)

[0051] Vestanat IPDI:

[0052] Isophorone diisocyanate; NCO content=37.5-37.8% (Hüls AG)

[0053] TBPIN:

[0054] Tert.butyl perisononanoate (Peroxid-Chemie GmbH)

[0055] TBPEH:

[0056] Tert.butylperoxy-2-ethylhexanoate (Peroxid-Chemie GmbH)

[0057] MEKP:

[0058] Methyl ethyl ketone peroxide (Peroxid-Chemie GmbH)

B) Production of the polyurethanes Stage 1 of the Process According tothe Invention Intermediate Product 1 (IP 1)

[0059] 100 g of isophorone diisocyanate were added dropwise over aperiod of 30 minutes at 80° C. to a mixture of 700 g of Photomer 3005 Fand 300 g of Photomer 4226. The mixture was then heated to 80° C. andstirred at that temperature for 30 mins. After cooling, the product wasobtained as a yellow-brown liquid (hereinafter referred to asintermediate product 1).

Intermediate Product 2 (IP 2)

[0060] 50 g of isophorone diisocyanate were added dropwise over a periodof 30 minutes at 80° C. to a mixture of 700 g of Photomer 3005 ″F and300 g of Photomer 4226. The mixture was then heated to 80° C. andstirred at that temperature for 30 mins. After cooling, the product wasobtained as a yellow-brown liquid (hereinafter referred to asintermediate product 2).

C) Radical Post-Crosslinking Stage 2 of the Process According to theInvention Example 1

[0061] 100 parts by weight of intermediate product 1 were mixed with 2parts by weight of TBPIN and TBPEH. The mixture was then cured for 30minutes at 140° C. The polymer obtained had a Shore D hardness of 78.

Example 2

[0062] 4 parts by weight of MEKP and 0.25 part by weight ofBeschleuniger C-101 were added to 100 parts by weight of intermediateproduct 1. The mixture was then cured for 30 minutes at 75° C. Theproduct obtained had a Shore D hardness of 75.

Example 3

[0063] 4 parts by weight of MEKP and 0.25 part by weight ofBeschleuniger C-101 were added to 100 parts by weight of intermediateproduct 2. The mixture was then cured for 30 minutes at 75° C. Theproduct obtained had a Shore D hardness of 65.

Example 4

[0064] 4 parts by weight of MEKP and 0.25 part by weight ofBeschleuniger C-101 were added to 100 parts by weight of intermediateproduct 1. The mixture was then cured for 6 days at 20° C. The productobtained had a Shore D hardness of 45.

1. A process for the production of radically post-crosslinked polymers,characterized in that, in a first stage, at least one or more compounds(a) which are reaction products of epoxidized fatty acid esters and/orepoxidized triglycerides with acrylic acid and/or methacrylic acid areconverted into the corresponding polyurethanes (a*) by reaction withaliphatic and/or aromatic isocyanates and, in a second stage, thepolyurethanes (a*) thus produced are subsequently subjected to radicalpost-crosslinking in the presence of at least one radical initiator (b).2. A process as claimed in claim 1, characterized in that a combinationof at least one compound (a) with at least one compound (c) is used inthe first stage, with the proviso that (c) is selected from polyolesters which contain two or more C═C double bonds per molecule.
 3. Aprocess as claimed in claim 1, characterized in that a combination of atleast one compound (a*) with at least one compound (c) is used in thesecond stage, with the proviso that (c) is selected from polyol esterswhich contain two or more C═C double bonds per molecule.
 4. A process asclaimed in any of claims 1 to 3, characterized in that, in the secondstage, the radical post-crosslinking is carried out in the presence of aradical initiator selected from the group consisting of tert.butylperisononanoate, tert.butylperoxy-2-ethylhexanoate and methyl ethylketone peroxide.
 5. A process as claimed in any of claims 1 to 4,characterized in that, in the second stage, the radicalpost-crosslinking is carried out in the presence of a transition metalcompound (d).
 6. A process as claimed in any of claims 1 to 5,characterized in that, in the second stage, the radicalpost-crosslinking is carried out in the presence of one or morecompounds (e) copolymerizable with the compounds (a*) selected from thegroup consisting of acrolein, acrylamide, vinyl acetate and styrene. 7.A process as claimed in any of claims 1 to 6, characterized in that thefirst and/or second stage is carried out in the presence of up to 20% byweight of additives for plastics—% by weight of the sum of all plasticadditives, based on the total quantity of the compounds (a) used.
 8. Theuse of polymers obtainable by the process claimed in any of claims 1 to7 as a matrix material for composites based on synthetic and/or naturalfibers.
 9. A polymer-based material obtainable by a process in which, ina first stage, at least one or more compounds (a) which are reactionproducts of epoxidized fatty acid esters and/or epoxidized triglycerideswith acrylic acid and/or methacrylic acid are converted into thecorresponding polyurethanes (a*) by reaction with aliphatic and/oraromatic isocyanates and, in a second stage, the polyurethanes (a*) thusproduced are subsequently subjected to radical post-crosslinking in thepresence of at least one radical initiator (b).
 10. A material asclaimed in claim 9, characterized in that the first and/or second stageof its production is/are carried out in the presence of up to 20% byweight of additives typical of plastics—% by weight of the sum of allplastic additives, based on the total quantity of the compounds (a)used.
 11. A material as claimed in claim 9 or 10, characterized in thatthe second stage of its production is carried out in the presence of 10to 70% by weight of synthetic and/or natural fibers—% by weight of thesum of all fibers, based on the total quantity of the compounds (a), (b)and optionally (c) and optionally (e) used.
 12. The use of the materialsclaimed in claim 11 for the production of structural components forvehicle and aircraft construction, the building industry, windowmanufacture, the furniture industry, the electronics industry, sportsequipment, toys, machine construction, the packaging industry,agriculture or the safety sector.